The goal of the Mentored Patient-Oriented Research Career Development Award (K23) is to facilitate training clinical practitioners in the area of patient-oriented clinical research. The application is separated into didactic and research components. The didactic component will provide education experiences that include introductory, specialty, and integrative courses. The combination of these courses will allow the candidate to develop independence and confidence in her ability to apply the scientific method. The research component will provide the candidate an opportunity to work closely with experienced clinical and basic science investigators. The research project combines 1) in vivo evaluations of Class II composite restorations placed in pediatric patients with 2) in vitro chemical, mechanical, and morphologic analyses of these restorations following exfoliation of the treated teeth. The candidate will develop a unique database that includes for each composite restoration clinical features e.g. surface staining, marginal integrity, recurrent caries, etc. The candidate working with her mentors will complete chemical, mechanical and morphologic characterization on the exfoliated samples, paying particular attention to breakdown at the composite/tooth interface. The juxtaposition of these analyses will provide critical, new data on changes within the composite material and/or at the material/tooth interface during function in the pediatric dental patient. The overall hypotheses of this project are that the clinical performance of Class II composite restorations placed in primary molars depends on the development of an impervious seal at the gingival margin and that a pre-treatment regimen that provides complete adhesive resin encapsulation of the treated dentin will result in a superior bond at these sites of the preparation. The specific aims will test the following hypotheses: in comparison to dentin pre-treatment regimen that acid-etches the dentin separately, self-etching adhesive will provide 1) improved bonding at the gingival margin of Class II composite restorations placed in primary molars, in vivo; 2) superior clinical performance at the gingival margin of Class II composite restorations placed in primary molars for up to 36 months in vivo; 3)enhanced infiltration of the dentin at the gingival margin of Class II composite restorations (in recovered specimens) as measured by Raman chemical imaging of the dentin/hybrid/adhesive/composite (d/h/a/c)interface; 4) greater modulus of elasticity with the dentin at the gingival margin as measured by scanning acoustic microscopy; 5) enhanced structural integrity at the d/h/a/c interface at the gingival margin.